Printed board with component mounting pin

ABSTRACT

A printed circuit board according to the present invention is a printed circuit board ( 4 ) including a component mounting pin ( 1 ) made of a metal wire to connect with a semiconductor chip ( 10 ). The semiconductor chip ( 10 ) is a surface mounting type semiconductor chip having an electrode pad on its mounting surface for use in a flip-chip mounting system. The component mounting pin ( 1 ) is formed by using wire-bonding technology. This printed circuit board ( 4 ) is able to decrease malconnections or disconnection caused by a difference between the coefficients of thermal expansion of the semiconductor chip ( 10 ) and the printed circuit board ( 4 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims the benefit of U.S.application Ser. No. 11/566,862, filed Dec. 5, 2006, which claimspriority of Japanese Patent Application No. 2005-356168, filed on Dec.9, 2005. The entire content of each of these applications isincorporated herein by reference to the extent that such incorporationdoes not create an issue of new matter.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to printed circuit boards, andmore particularly to a printed circuit board with a conductive componentmounting pin.

2. Description of the Related Art

[Patent Document 1]: Japanese Patent Laid-Open Publication No.2005-183466 “Multilayer Printed Circuit Board” (published on Jul. 7,2005)

The Background Art of the Patent Document 1 has described a flip-chipmounting system printed circuit board using suitable technology such assolder bump in which a solder resist layer 70 is formed on an upperlayer of a via hole 160 and a conductor circuit 158, bumps 76U and 76Dbeing formed on the via hole 160 and the conductor circuit 158 throughan opening portion 71 of the solder resist layer 70. An IC (integratedcircuit, not shown) chip may be electrically connected to the printedcircuit board by C4 (flip-chip) mounting.

However, the above Patent Document 1 fails to mention a printed circuitboard with a component mounting pin disclosed in the present invention.

SUMMARY OF THE INVENTION

On the other hand, as an integration degree of semiconductor apparatusis increasing more in recent years, a chip size thereof also is becomingenormous. If an electronic device in the mounting state in which anelectrode pad of an electronic component (e.g. semiconductor chip) of agigantic size and a land of a printed circuit board are soldered isexposed to rise and fall of an ambient temperature, then it isunavoidable that a soldered portion will be broken due to a differencebetween coefficients of thermal expansion of the electronic componentand the printed circuit board.

Therefore, a demand of developing a printed circuit board in whichmalconnections or disconnections caused by a difference between thecoefficients of thermal expansion of the electronic component and theprinted circuit board can be decreased even when a highly-integratedsemiconductor chip is mounted thereon has increased so far.

In view of the aforesaid aspects, an object of the present invention isto provide a printed circuit board in which malconnections ordisconnections caused by a difference between the coefficients ofthermal expansion of an electronic component and a printed circuit boardcan be decreased even when a highly-integrated electronic component(e.g. semiconductor chip) is mounted thereon.

A printed circuit board of the present invention includes a componentmounting pin made of a conductive material to connect with an electroniccomponent.

Further, in the printed circuit board, said component mounting pin maybe formed of a metal wire.

Further, in the printed circuit board, said electronic component may bea surface mounting type semiconductor chip having an electrode pad onits mounting surface for use in a flip-chip mounting system.

Further, in the printed circuit board, said component mounting pin ismade of a material with suitable properties such as flexibility,elasticity and pliability.

Further, in the printed circuit board, said component mounting pin maybe made of a material with low electric resistance.

Further, in the printed circuit board, said component mounting pin maybe formed by wire bonding technology.

Further, in the printed circuit board, said component mounting pin maybe formed as a pin of any shape selected from a group of pin shapes of avertical S-like pin, a horizontal S-like pin, a curved pin, a loop-likepin, a spiral pin, a spring-like pin, a circular pin and an ellipticpin.

Further, in the printed circuit board, said component mounting pin maybe coated with a protective coating.

Further, an electronic device comprising:

a printed circuit board with a component mounting pin; and

an electronic component, wherein said component mounting pin is urgedagainst an electrode pad of said electronic component.

Further, an electronic device of the present invention comprises: aprinted circuit board with a component mounting pin; and an electroniccomponent, wherein said component mounting pin is connected to anelectrode pad of said electronic component by solder-joint through asolder bump.

Further, in the an electronic device, said component mounting pin may bea mechanical element capable of absorbing mechanical energy applied toeither of or both of a semiconductor apparatus and a printed circuitboard through elasticity or deformation.

Further, in the electronic device, said printed circuit board may befixed to a case of said electronic device.

Further, in the an electronic device, said printed circuit board andsaid electronic component may be fixed to each other by adhesive.

Further, a method of manufacturing a printed circuit board with acomponent mounting pin of the present invention comprises the steps of:(a) a step for conveying a metal wire onto an electrode land of aprinted circuit board attached to a suitable positioning apparatus; (b)a step for recognizing a land bonding point of said printed circuitboard; (c) a step for compression-bonding and joining a tip end of ametal wire to said land bonding point; (d) a step for looping said metalwire; (e) a step for cutting said metal wire; (f) a step for forming aball by fusing a tip end portion of said cut metal wire; and (g) a stepfor moving a metal wire to the next land of said printed circuit board.

Further, in the method of manufacturing a printed circuit with acomponent mounting pin, said steps (a) to (g) may be executedrepeatedly.

Further, in the method of manufacturing a printed circuit with acomponent mounting pin, said step (c) may be executed by usingthermocompression bonding system and ultrasonic waves at the same time.

According to the present invention, a printed circuit board may beprovided in which malconnections or disconnections caused by adifference between the coefficients of thermal expansion of anelectronic component and a printed circuit board can be decreased evenwhen a highly-integrated electronic component is mounted thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing part of an arrangement of a printed circuitboard with a component mounting pin;

FIG. 2A is a diagram showing a method of mounting an electronic devicein which a component mounting pin of a printed circuit board is urgedagainst an electrode pad of a semiconductor chip;

FIG. 2B is a diagram showing a method of mounting an electronic devicein which a component mounting pin of a printed circuit board isconnected to an electrode pad of a semiconductor chip by solder-jointthrough solder bump;

FIGS. 3A to 3F are respectively diagrams to which reference will be madein explaining various shapes available for the component mounting pin ofthe printed circuit board; and

FIGS. 4A to 4F are respectively diagrams showing respective steps of amethod of manufacturing a printed circuit board with a componentmounting pin.

EXPLANATION OF REFERENCE NUMERALS

1: component mounting pin, 2: insulating layer, 4: printed circuitboard, 5: land, electrode land, 6: filled via, 10: semiconductor via,11: pad, electrode pad, 12: solder bump, 21: electric torch, 22: ball,23: capillary, 24: clamper, 25: metal wire, 26: spool, 27: air tension,28: position detecting camera

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A printed circuit board with a component mounting pin according to theembodiments of the present invention will be described below in detailwith reference to the drawings. In the following drawings, identicalelements and parts are denoted by identical reference numerals andtherefore need not be described.

[Printed Circuit Board with Component Mounting Pin ]

FIG. 1 of the accompanying drawings is a diagram showing part of anarrangement of a printed circuit board with a component mounting pin. Asshown in FIG. 1, a printed circuit board 4 includes a conductivecomponent mounting pin 1 to connect with an electronic component, e.g. asemiconductor chip (not shown). This component mounting pin 1 can beformed by using wire bonding technology, for example.

The printed circuit board with the component mounting pin according tothe embodiment of the present invention is characterized in that acomponent mounting pin is formed on an electrode land of a printedcircuit board in advance, the component mounting pin being electricallyconnected to the electrode pad of a semiconductor chip in a surfacemounting fashion (i.e. two-dimensional mounting: mounting in which ajoint member in flip-chip mounting system is changed from solder topin).

The printed circuit board 4 with the component mounting pin 1 ischaracterized by the conductive component mounting pin 1 electricallyconnected to an electrode land (outermost layer conductor) 5.Alternatively, the electrode land 5 may be formed on a filled via-hole6. A rest of arrangement of the printed circuit board 4 can be changedfreely. Since the embodiment of the present invention is characterizedby the outermost layer conductor, the printed circuit board 4 iscomposed of an insulating layer 2 on which the outermost layer conductor5 is formed and other layer 3 formed of a predetermined insulating layerand a conductor layer and hence the insulating layer 2 and other layer 3will be explained separately in order to understand the presentinvention more clearly. It should be noted that a desired solder resistlayer may be formed on the upper surface of the insulating layer 2.

One end of the component mounting pin 1 is connected electrically to theelectrode land 5 and the other end thereof is erected from the printedcircuit board 4. The component mounting pin 1 may be coated with adesired conductive protecting coating (not shown). The printed circuitboard 4 is connected to a semiconductor apparatus (not shown) throughthis component mounting pin 1.

The component mounting pin 1 is made of a material having suitableproperties such as flexibility, elasticity and pliability and the like.Preferably, the component mounting pin 1 should be made of a materialwith low electric resistance in addition to flexibility, elasticity andpliability. Typically, the component mounting pin 1 may be formed of ametal wire.

FIGS. 2A and 2B are respectively diagrams showing methods of mountingelectronic devices including the printed circuit board 4 with thecomponent mounting pin 1 and a semiconductor chip 10. The formerelectronic device shown in FIG. 2A and the latter electronic deviceshown in FIG. 2B are different from each other in that while thecomponent mounting pin 1 is urged against an electrode pad 11 of thesemiconductor chip 10 as shown in FIG. 2A, the component mounting pin 1is solder-connected to the electrode pad 11 of the semiconductor chip 10by using a pin solder bump 12 as shown in FIG. 2B.

In the electronic device shown in FIG. 2A, the component mounting pin 1of the printed circuit board 4 electrically contacts with the electrodepad 11 formed on the semiconductor chip 10 to maintain electricconnection. The printed circuit board 4 and the semiconductor chip 10may be fixed to each other by any method. For example, both of theprinted circuit board 4 and the semiconductor chip 10 may be fixed to acase of an electronic device, although not shown. Alternatively, theprinted circuit board 4 and the semiconductor chip 10 may both be fixedto each other by using adhesive such as resin.

The mounting structure shown in FIG. 2A is characterized in that themember lying between the semiconductor device 10 and the printed circuitboard 4 to connect them is varied from the related-art solder bump tothe component mounting pin 1. Since the component mounting pin 1 is madeof the material with suitable properties such as flexibility, elasticityand pliability, it can ensure electric connection between thesemiconductor device 10 and the printed circuit board 4 when beingpressed against the electrode pad 11. Further, it is to be understoodthat the component mounting pin 1 might be a mechanical element toabsorb force (mechanical energy) applied to either of or both of thesemiconductor device 10 and the printed circuit board 4 by elasticity ordeformation. Hence, the component mounting pin 1 is able to decreasemalconnections or disconnections caused by a difference between thecoefficients of thermal expansion of the semiconductor device 10 and theprinted circuit board 4.

Further, since the component mounting pin 1 is very short in length,there can be obtained excellent electric characteristics from astandpoint of matching of a characteristic impedance Z.sub.0 and alsofrom a standpoint of increasing a propagation speed of an electricsignal. Similarly, when the component mounting pin 1 is formed of amaterial with low electric resistance, it is possible to avoid uselessvoltage drop. For example, a component mounting pin might be made of Cu(copper), Au (gold), Ag (silver) or alloy of them. Alternatively, acomponent mounting pin might be a component mounting pin which issurface-finished by these metals.

Further, since the component mounting pin 1 is erected at its other endfrom the printed circuit board 4 as described above, it can be enclosedwith the air to thereby increase a speed at which a signal istransmitted. Furthermore, when the component mounting pin 1 mechanicallycontacts with the electrode pad 10 of the semiconductor chip 10 by forceof repulsion, it is possible to maintain satisfactory electricconnection between the semiconductor chip 10 and the printed circuitboard 4.

Furthermore, the printed circuit board 4 with the component mounting pin1 according to the embodiment of the present invention is characterizedby the component mounting pin 1 in electric contact with the electrodeland 5 and a rest of the printed circuit board 4 can be changed freely.Hence, the present invention can be applied to other suitable circuitboards such as a large printed wiring board and a coreless printedcircuit board that tends to warp. Further, since the semiconductor chip10 and the printed circuit board 4 are connected together not bysoldering but by mechanical contact of the component mounting pin 1, theembodiment of the present invention has a merit that a thermal budgetduring a reflow process ant others will not be left.

FIG. 2B is a diagram showing a mounting structure in which electricconnection can be maintained by connecting the component mounting pin 1of the printed circuit board 4 and the semiconductor chip 10 viasoldering. As shown in FIG. 2B, a desired solder bump 12 may be providedat the tip end of the component mounting pin 1 of the printed circuitboard 4 and in the state in which the component mounting pin 1 isbrought in electric contact with the semiconductor chip 10, thecomponent mounting pin 1 and the electrode pad 11 of the semiconductorchip 10 may be connected by soldering through solder reflow technology.Furthermore, if requested, the printed circuit board 4 and thesemiconductor chip 10 might be fixed to each other by theabove-mentioned methods.

FIGS. 3A to 3F are respectively diagrams to which reference will be madein explaining various shapes available for the component mounting pin 1.The component mounting pin 1 is made of the material with suitableproperties such as flexibility, elasticity and pliability and it isurged against the electrode pad 11 of the semiconductor chip 10 as shownin FIG. 2A. In order to realize this mounting structure, the followingshapes are available for the component mounting pin 1.

FIG. 3A shows a component mounting pin 1-1 which is shaped as a verticalS-like pin. FIG. 3B shows a component mounting pin 1-2 which is shapedas a horizontal S-like pin. FIG. 3C shows a component mounting pin 1-3which is shaped like a curved pin. FIG. 3D shows a component mountingpin 1-4 which is shaped as a loop-like pin. FIG. 3E shows a componentmounting pin 1-5 which is shaped as a spiral or spring-like pin. FIG. 3Fshows a component mounting pin 1-6 which is shaped as a circular orelliptic pin. These shapes of the component mounting pin 1 areillustrated by way of example and any shape of the component mountingpin 1 can be used insofar as the component mounting pin 1 can be urgedagainst the electrode pad 11 of the semiconductor chip 10.

[Method of Manufacturing Printed Circuit Board with Computer MountingPin ]

A method of manufacturing a printed circuit board with a componentmounting pin will be now be described with reference to FIGS. 4A to 4Din comparison with related-art wire bonding technology.

First, the related-art wire bonding technology, e.g. nail-head bondingincludes the following steps of a step (1) for conveying a lead frame onwhich a semiconductor chip is mounted, a step (2) for recognizing theposition of a bonding pad of the semiconductor chip by a patternrecognition mechanism, a step (3) for executing bonding on thesemiconductor chip side, a step (4) for looping (shaping) of a metalwire, a step (5) for bonding the semiconductor chip on the printedcircuit board at its electrode land of the semiconductor chip adjacentarea, a step (6) for cutting the metal wire, a step (7) for fusing thetip end of the thus cut metal wire to form a ball and a step (8) formoving the metal wire to the next semiconductor chip.

In the method of manufacturing the printed circuit board 4 with thecomponent mounting pin 1 according to the embodiment of the presentinvention, the above-described steps of the step (1) of “conveyance”,the step (2) of “position recognition”, the step (5) of “bonding ontothe land of the printed circuit board”, the step (4) of “looping(shaping) of the metal wire”, the step (6) of “cutting of the metalwire”, the step of (7) “forming of the ball” and the step of (8) “movingof the metal wire” are executed, in that order.

In this case, it is to be assumed that the printed circuit board 4 inwhich the electrode land 5 is formed on the component mounting surfacehas already been fabricated. The following steps are executed by the useof this printed circuit board 4.

(a) Conveyance (see FIG. 4A):

The printed circuit board 4 is attached to a suitable positioningapparatus (not shown). As shown in FIG. 4A, a metal wire 25 is suppliedfrom a spool 26 through holes of an air tension 27, a damper 24 and acapillary 23 to the electrode land 5 of the printed circuit board 4. Atip end of the metal wire 25 is shaped like a ball 22.

(b) Position recognition (see FIG. 4B):

The position of the electrode 5 of the printed circuit board 4 ismeasured by a bonder position recognition mechanism using a positiondetecting camera 28 and a bonding point of the electrode land 5 iscalculated.

(c) Bonding onto the electrode land of the printed circuit board (seeFIG. 4C):

The ball 22 of the metal wire 25 is urged against the bonding point ofthe electrode land 5 by the capillary 23 and the ball 22 is joined tothe electrode land 5 of the printed circuit board 4 by diffusion ofmetal. In this case, in order to decrease damages caused on the printedcircuit board 4 by heat, it is preferable that the step (c) should beexecuted by using thermocompression bonding system and ultrasonic wavestogether.

(d) Looping (shaping) of metal wire (see FIG. 4D):

The metal wire 25 is shaped while elevating the capillary 23. The metalwire 25 should be reversed right and left and up and down in order toprovide a metal wire of a desired shape.

(e) Cutting of metal wire (see FIG. 4E):

The metal wire 25 is cut by the damper 24 when the capillary 23 iselevated.

(f) Forming of ball (see FIG. 4F):

An electric torch 21 applies discharged electricity to the tip endportion of the thus cut metal wire 25 to fuse the tip end of the metalwire 25 to thereby form a ball. At this stage, the metal wire 25 maybecome available as the component mounting pin 1.

(g) Movement (not shown):

A metal wire is moved onto an electrode land 5 of the next printedcircuit board 4.

It is possible to manufacture a printed circuit board with a componentmounting pin by repeatedly executing the above-described steps (a) to(g) at a high speed. It should be noted that the step (f) can becanceled.

[The Others]

While the embodiments of the printed circuit board with the componentmounting pin according to the present invention have been described sofar, it is needless to say that the present invention is not limited tothose embodiments.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1-8. (canceled)
 9. A method of mounting an electronic component on aprinted circuit board comprising the steps of: (a) providing theelectronic component having an electrode pad thereon; (b) providing aprinted circuit board comprising an insulating layer and an outermostconductor layer formed on the insulating layer and including anelectrode land; (c) conveying a metal wire to the electrode land of theprinted circuit board using a positioning apparatus, the metal wirebeing made of a conductive material having a property of at least one offlexibility, elasticity and pliability; (d) recognizing a land bondingpoint of the electrode land; (e) compression-bonding and joining a tipend of the metal wire to the land bonding point of the electrode land;(f) looping the metal wire; (g) cutting the metal wire; (h) fusing a tipend portion of the cut metal wire to form a ball thereon to form acomponent mounting pin for mounting the electronic component; (i)conveying the metal wire to a next land of the printed circuit board;and (j) after executing (c)-(i) repeatedly to form a plurality ofcomponent mounting pins on the printed circuit board, fixing theelectronic component and the printed circuit board to each other byurging the component mounting pin against the electrode pad of theelectronic component and electrically connecting the mounting pin to theelectrode pad by mechanical force of repulsion without soldering.
 10. Amethod of mounting an electronic component on a printed circuit boardcomprising the steps of: (a) providing the electronic componentincluding a semiconductor chip having an electrode pad on a surfacethereof; (b) providing a printed circuit board comprising an insulatinglayer and an outermost conductor layer formed on the insulating layerand including an electrode land; (c) conveying a metal wire to theelectrode land of the printed circuit board using a positioningapparatus, the metal wire being made of a conductive material having aproperty of at least one of flexibility, elasticity and pliability; (d)recognizing a land bonding point of the electrode land; (e)compression-bonding and joining a tip end of the metal wire to the landbonding point; (f) looping the metal wire; (g) cutting the metal wire;(h) fusing a tip end portion of the cut metal wire to form a ballthereon to form a component mounting pin for mounting the electroniccomponent; (i) moving the metal wire to a next land of the printedcircuit board; and (k) after executing (c)-(i) repeatedly to form aplurality of component mounting pins on the printed circuit board,fixing the electronic component and the printed circuit board to eachother by providing the surface of the semiconductor chip opposite to thesurface of the insulating layer having the electrode land thereon, andconnecting the component mounting pin to an electrode pad of theelectronic component through a solder bump.
 11. The method according toclaim 9, wherein said providing an electronic component comprisesproviding a surface mounting type semiconductor chip having an electrodepad on its mounting surface.
 12. The method according to claim 9,further comprising making said component mounting pin of a material withlow electric resistance.
 13. The method according to claim 9, furthercomprising forming said component mounting pin as a pin of any shapeselected from the following group of pin shapes: a vertical S-like pin,a horizontal S-like pin, a curved pin, a loop-like pin, a spiral pin, aspring-like pin, or a circular pin and an elliptic pin.
 14. The methodaccording to claim 9, further comprising coating said component mountingpin with a protective coating.
 15. The method according to claim 9,further comprising forming said component mounting pin as a mechanicalelement capable of absorbing mechanical energy applied to either of orboth of a semiconductor apparatus and a printed circuit board throughelasticity or deformation.
 16. The method according to claim 9, furthercomprising fixing said printed circuit board to a case of saidelectronic device.
 17. The method according to claim 9, furthercomprising fixing said printed circuit board and said electroniccomponent to each other by adhesive.
 18. The method according to claim10, wherein said providing an electronic component comprises providing asurface mounting type semiconductor chip having an electrode pad on itsmounting surface.
 19. The method according to claim 10, furthercomprising making said component mounting pin of a material with lowelectric resistance.
 20. The method according to claim 10, furthercomprising forming said component mounting pin as a pin of any shapeselected from the following group of pin shapes: a vertical S-like pin,a horizontal S-like pin, a curved pin, a loop-like pin, a spiral pin, aspring-like pin, or a circular pin and an elliptic pin.
 21. The methodaccording to claim 10, further comprising coating said componentmounting pin with a protective coating.
 22. The method according toclaim 10, further comprising forming said component mounting pin as amechanical element capable of absorbing mechanical energy applied toeither of or both of a semiconductor apparatus and a printed circuitboard through elasticity or deformation.
 23. The method according toclaim 10, further comprising fixing said printed circuit board to a caseof said electronic device.
 24. The method according to claim 10, furthercomprising fixing said printed circuit board and said electroniccomponent to each other by adhesive.